Chris@16: 
Chris@16: #ifndef DATE_TIME_FORMAT_DATE_PARSER_HPP__
Chris@16: #define DATE_TIME_FORMAT_DATE_PARSER_HPP__
Chris@16: 
Chris@16: /* Copyright (c) 2004-2005 CrystalClear Software, Inc.
Chris@16:  * Use, modification and distribution is subject to the 
Chris@16:  * Boost Software License, Version 1.0. (See accompanying
Chris@16:  * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
Chris@16:  * Author: Jeff Garland, Bart Garst
Chris@101:  * $Date$
Chris@16:  */
Chris@16: 
Chris@16: 
Chris@16: #include "boost/lexical_cast.hpp"
Chris@16: #include "boost/date_time/string_parse_tree.hpp"
Chris@16: #include "boost/date_time/strings_from_facet.hpp"
Chris@16: #include "boost/date_time/special_values_parser.hpp"
Chris@16: #include <string>
Chris@16: #include <vector>
Chris@16: #include <sstream>
Chris@16: #include <iterator>
Chris@16: #ifndef BOOST_NO_STDC_NAMESPACE
Chris@16: #  include <cctype>
Chris@16: #else
Chris@16: #  include <ctype.h>
Chris@16: #endif
Chris@16: 
Chris@16: #ifdef BOOST_NO_STDC_NAMESPACE
Chris@16: namespace std {
Chris@16:   using ::isspace;
Chris@16:   using ::isdigit;
Chris@16: }
Chris@16: #endif
Chris@16: namespace boost { namespace date_time {
Chris@16:   
Chris@16: //! Helper function for parsing fixed length strings into integers
Chris@16: /*! Will consume 'length' number of characters from stream. Consumed 
Chris@16:  * character are transfered to parse_match_result struct. 
Chris@16:  * Returns '-1' if no number can be parsed or incorrect number of 
Chris@16:  * digits in stream. */
Chris@16: template<typename int_type, typename charT>
Chris@16: inline
Chris@16: int_type
Chris@16: fixed_string_to_int(std::istreambuf_iterator<charT>& itr,
Chris@16:                     std::istreambuf_iterator<charT>& stream_end,
Chris@16:                     parse_match_result<charT>& mr,
Chris@16:                     unsigned int length,
Chris@16:                     const charT& fill_char)
Chris@16: {
Chris@16:   //typedef std::basic_string<charT>  string_type;
Chris@16:   unsigned int j = 0;
Chris@16:   //string_type s;
Chris@16:   while (j < length && itr != stream_end && 
Chris@16:       (std::isdigit(*itr) || *itr == fill_char)) {
Chris@16:     if(*itr == fill_char) {
Chris@16:       /* Since a fill_char can be anything, we convert it to a zero. 
Chris@16:        * lexical_cast will behave predictably when zero is used as fill. */
Chris@16:       mr.cache += ('0'); 
Chris@16:     }
Chris@16:     else {
Chris@16:       mr.cache += (*itr);
Chris@16:     }
Chris@16:     itr++;
Chris@16:     j++;
Chris@16:   }
Chris@101:   int_type i = static_cast<int_type>(-1);
Chris@16:   // mr.cache will hold leading zeros. size() tells us when input is too short.
Chris@16:   if(mr.cache.size() < length) {
Chris@16:     return i;
Chris@16:   }
Chris@16:   try {
Chris@16:     i = boost::lexical_cast<int_type>(mr.cache);
Chris@16:   }catch(bad_lexical_cast&){
Chris@16:     // we want to return -1 if the cast fails so nothing to do here
Chris@16:   }
Chris@16:   return i;
Chris@16: }
Chris@16: 
Chris@16: //! Helper function for parsing fixed length strings into integers
Chris@16: /*! Will consume 'length' number of characters from stream. Consumed 
Chris@16:  * character are transfered to parse_match_result struct. 
Chris@16:  * Returns '-1' if no number can be parsed or incorrect number of 
Chris@16:  * digits in stream. */
Chris@16: template<typename int_type, typename charT>
Chris@16: inline
Chris@16: int_type
Chris@16: fixed_string_to_int(std::istreambuf_iterator<charT>& itr,
Chris@16:                     std::istreambuf_iterator<charT>& stream_end,
Chris@16:                     parse_match_result<charT>& mr,
Chris@16:                     unsigned int length)
Chris@16: {
Chris@16:   return fixed_string_to_int<int_type, charT>(itr, stream_end, mr, length, '0');
Chris@16: }
Chris@16: 
Chris@16: //! Helper function for parsing varied length strings into integers
Chris@16: /*! Will consume 'max_length' characters from stream only if those 
Chris@16:  * characters are digits. Returns '-1' if no number can be parsed. 
Chris@16:  * Will not parse a number preceeded by a '+' or '-'. */
Chris@16: template<typename int_type, typename charT>
Chris@16: inline
Chris@16: int_type
Chris@16: var_string_to_int(std::istreambuf_iterator<charT>& itr,
Chris@16:                   const std::istreambuf_iterator<charT>& stream_end,
Chris@16:                   unsigned int max_length)
Chris@16: {
Chris@16:   typedef std::basic_string<charT>  string_type;
Chris@16:   unsigned int j = 0;
Chris@16:   string_type s;
Chris@16:   while (itr != stream_end && (j < max_length) && std::isdigit(*itr)) {
Chris@16:     s += (*itr);
Chris@16:     ++itr;
Chris@16:     ++j;
Chris@16:   }
Chris@101:   int_type i = static_cast<int_type>(-1);
Chris@16:   if(!s.empty()) {
Chris@16:     i = boost::lexical_cast<int_type>(s);
Chris@16:   }
Chris@16:   return i;
Chris@16: }
Chris@16: 
Chris@16: 
Chris@16: //! Class with generic date parsing using a format string
Chris@16: /*! The following is the set of recognized format specifiers
Chris@16:  -  %a - Short weekday name
Chris@16:  -  %A - Long weekday name
Chris@16:  -  %b - Abbreviated month name
Chris@16:  -  %B - Full month name
Chris@16:  -  %d - Day of the month as decimal 01 to 31
Chris@16:  -  %j - Day of year as decimal from 001 to 366
Chris@16:  -  %m - Month name as a decimal 01 to 12
Chris@16:  -  %U - Week number 00 to 53 with first Sunday as the first day of week 1?
Chris@16:  -  %w - Weekday as decimal number 0 to 6 where Sunday == 0
Chris@16:  -  %W - Week number 00 to 53 where Monday is first day of week 1
Chris@16:  -  %x - facet default date representation
Chris@16:  -  %y - Year without the century - eg: 04 for 2004
Chris@16:  -  %Y - Year with century 
Chris@16: 
Chris@16:  The weekday specifiers (%a and %A) do not add to the date construction,
Chris@16:  but they provide a way to skip over the weekday names for formats that
Chris@16:  provide them.
Chris@16: 
Chris@16:  todo -- Another interesting feature that this approach could provide is
Chris@16:          an option to fill in any missing fields with the current values
Chris@16:          from the clock.  So if you have %m-%d the parser would detect
Chris@16:          the missing year value and fill it in using the clock. 
Chris@16: 
Chris@16:  todo -- What to do with the %x.  %x in the classic facet is just bad...
Chris@16: 
Chris@16:  */
Chris@16: template<class date_type, typename charT>
Chris@16: class format_date_parser
Chris@16: {
Chris@16:  public:
Chris@16:   typedef std::basic_string<charT>        string_type;
Chris@16:   typedef std::basic_istringstream<charT>  stringstream_type;
Chris@16:   typedef std::istreambuf_iterator<charT> stream_itr_type;
Chris@16:   typedef typename string_type::const_iterator const_itr;
Chris@16:   typedef typename date_type::year_type  year_type;
Chris@16:   typedef typename date_type::month_type month_type;
Chris@16:   typedef typename date_type::day_type day_type;
Chris@16:   typedef typename date_type::duration_type duration_type;
Chris@16:   typedef typename date_type::day_of_week_type day_of_week_type;
Chris@16:   typedef typename date_type::day_of_year_type day_of_year_type;
Chris@16:   typedef string_parse_tree<charT> parse_tree_type;
Chris@16:   typedef typename parse_tree_type::parse_match_result_type match_results;
Chris@16:   typedef std::vector<std::basic_string<charT> > input_collection_type;
Chris@16: 
Chris@16:   // TODO sv_parser uses its default constructor - write the others
Chris@16:   
Chris@16:   format_date_parser(const string_type& format_str,
Chris@16:                      const input_collection_type& month_short_names,
Chris@16:                      const input_collection_type& month_long_names,
Chris@16:                      const input_collection_type& weekday_short_names,
Chris@16:                      const input_collection_type& weekday_long_names) :
Chris@16:     m_format(format_str),
Chris@16:     m_month_short_names(month_short_names, 1),
Chris@16:     m_month_long_names(month_long_names, 1),
Chris@16:     m_weekday_short_names(weekday_short_names),
Chris@16:     m_weekday_long_names(weekday_long_names)
Chris@16:   {}
Chris@16:   
Chris@16:   format_date_parser(const string_type& format_str,
Chris@16:                      const std::locale& locale) :
Chris@16:     m_format(format_str),
Chris@16:     m_month_short_names(gather_month_strings<charT>(locale), 1),
Chris@16:     m_month_long_names(gather_month_strings<charT>(locale, false), 1),
Chris@16:     m_weekday_short_names(gather_weekday_strings<charT>(locale)),
Chris@16:     m_weekday_long_names(gather_weekday_strings<charT>(locale, false))
Chris@16:   {}
Chris@16: 
Chris@16:   format_date_parser(const format_date_parser<date_type,charT>& fdp)
Chris@16:   {
Chris@16:     this->m_format = fdp.m_format;
Chris@16:     this->m_month_short_names = fdp.m_month_short_names;
Chris@16:     this->m_month_long_names = fdp.m_month_long_names;
Chris@16:     this->m_weekday_short_names = fdp.m_weekday_short_names;
Chris@16:     this->m_weekday_long_names = fdp.m_weekday_long_names;
Chris@16:   }
Chris@16:   
Chris@16:   string_type format() const
Chris@16:   {
Chris@16:     return m_format;
Chris@16:   }
Chris@16: 
Chris@16:   void format(string_type format_str)
Chris@16:   {
Chris@16:     m_format = format_str;
Chris@16:   }
Chris@16: 
Chris@16:   void short_month_names(const input_collection_type& month_names)
Chris@16:   {
Chris@16:     m_month_short_names = parse_tree_type(month_names, 1);
Chris@16:   }
Chris@16:   void long_month_names(const input_collection_type& month_names)
Chris@16:   {
Chris@16:     m_month_long_names = parse_tree_type(month_names, 1);
Chris@16:   }
Chris@16:   void short_weekday_names(const input_collection_type& weekday_names)
Chris@16:   {
Chris@16:     m_weekday_short_names = parse_tree_type(weekday_names);
Chris@16:   }
Chris@16:   void long_weekday_names(const input_collection_type& weekday_names)
Chris@16:   {
Chris@16:     m_weekday_long_names = parse_tree_type(weekday_names);
Chris@16:   }
Chris@16: 
Chris@16:   date_type
Chris@16:   parse_date(const string_type& value, 
Chris@16:              const string_type& format_str,
Chris@16:              const special_values_parser<date_type,charT>& sv_parser) const
Chris@16:   {
Chris@16:     stringstream_type ss(value);
Chris@16:     stream_itr_type sitr(ss);
Chris@16:     stream_itr_type stream_end;
Chris@16:     return parse_date(sitr, stream_end, format_str, sv_parser);
Chris@16:   }
Chris@16: 
Chris@16:   date_type
Chris@16:   parse_date(std::istreambuf_iterator<charT>& sitr, 
Chris@16:              std::istreambuf_iterator<charT>& stream_end,
Chris@16:              const special_values_parser<date_type,charT>& sv_parser) const
Chris@16:   {
Chris@16:     return parse_date(sitr, stream_end, m_format, sv_parser);
Chris@16:   }
Chris@16: 
Chris@16:   /*! Of all the objects that the format_date_parser can parse, only a 
Chris@16:    * date can be a special value. Therefore, only parse_date checks 
Chris@16:    * for special_values. */
Chris@16:   date_type
Chris@16:   parse_date(std::istreambuf_iterator<charT>& sitr, 
Chris@16:              std::istreambuf_iterator<charT>& stream_end,
Chris@16:              string_type format_str,
Chris@16:              const special_values_parser<date_type,charT>& sv_parser) const
Chris@16:   {
Chris@16:     bool use_current_char = false;
Chris@16:     
Chris@16:     // skip leading whitespace
Chris@16:     while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; } 
Chris@16: 
Chris@16:     short year(0), month(0), day(0), day_of_year(0);// wkday(0); 
Chris@16:     /* Initialized the following to their minimum values. These intermediate 
Chris@16:      * objects are used so we get specific exceptions when part of the input 
Chris@16:      * is unparsable. 
Chris@16:      * Ex: "205-Jan-15" will throw a bad_year, "2005-Jsn-15"- bad_month, etc.*/
Chris@16:     year_type t_year(1400);
Chris@16:     month_type t_month(1);
Chris@16:     day_type t_day(1);
Chris@16:     day_of_week_type wkday(0);
Chris@16:     
Chris@16:     
Chris@16:     const_itr itr(format_str.begin());
Chris@16:     while (itr != format_str.end() && (sitr != stream_end)) {
Chris@16:       if (*itr == '%') {
Chris@16:         if ( ++itr == format_str.end())
Chris@16:         	break;
Chris@16:         if (*itr != '%') {
Chris@16:           switch(*itr) {
Chris@16:           case 'a': 
Chris@16:             {
Chris@16:               //this value is just throw away.  It could be used for
Chris@16:               //error checking potentially, but it isn't helpful in 
Chris@16:               //actually constructing the date - we just need to get it
Chris@16:               //out of the stream
Chris@16:               match_results mr = m_weekday_short_names.match(sitr, stream_end);
Chris@16:               if(mr.current_match == match_results::PARSE_ERROR) {
Chris@16:                 // check special_values
Chris@16:                 if(sv_parser.match(sitr, stream_end, mr)) {
Chris@16:                   return date_type(static_cast<special_values>(mr.current_match));
Chris@16:                 }
Chris@16:               }
Chris@16:               wkday = mr.current_match;
Chris@16:               if (mr.has_remaining()) {
Chris@16:                 use_current_char = true;
Chris@16:               }
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'A': 
Chris@16:             {
Chris@16:               //this value is just throw away.  It could be used for
Chris@16:               //error checking potentially, but it isn't helpful in 
Chris@16:               //actually constructing the date - we just need to get it
Chris@16:               //out of the stream
Chris@16:               match_results mr = m_weekday_long_names.match(sitr, stream_end);
Chris@16:               if(mr.current_match == match_results::PARSE_ERROR) {
Chris@16:                 // check special_values
Chris@16:                 if(sv_parser.match(sitr, stream_end, mr)) {
Chris@16:                   return date_type(static_cast<special_values>(mr.current_match));
Chris@16:                 }
Chris@16:               }
Chris@16:               wkday = mr.current_match;
Chris@16:               if (mr.has_remaining()) {
Chris@16:                 use_current_char = true;
Chris@16:               }
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'b': 
Chris@16:             {
Chris@16:               match_results mr = m_month_short_names.match(sitr, stream_end);
Chris@16:               if(mr.current_match == match_results::PARSE_ERROR) {
Chris@16:                 // check special_values
Chris@16:                 if(sv_parser.match(sitr, stream_end, mr)) {
Chris@16:                   return date_type(static_cast<special_values>(mr.current_match));
Chris@16:                 }
Chris@16:               }
Chris@16:               t_month = month_type(mr.current_match);
Chris@16:               if (mr.has_remaining()) {
Chris@16:                 use_current_char = true;
Chris@16:               }
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'B': 
Chris@16:             {
Chris@16:               match_results mr = m_month_long_names.match(sitr, stream_end);
Chris@16:               if(mr.current_match == match_results::PARSE_ERROR) {
Chris@16:                 // check special_values
Chris@16:                 if(sv_parser.match(sitr, stream_end, mr)) {
Chris@16:                   return date_type(static_cast<special_values>(mr.current_match));
Chris@16:                 }
Chris@16:               }
Chris@16:               t_month = month_type(mr.current_match);
Chris@16:               if (mr.has_remaining()) {
Chris@16:                 use_current_char = true;
Chris@16:               }
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'd': 
Chris@16:             {
Chris@16:               match_results mr;
Chris@16:               day = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 2);
Chris@16:               if(day == -1) {
Chris@16:                 if(sv_parser.match(sitr, stream_end, mr)) {
Chris@16:                   return date_type(static_cast<special_values>(mr.current_match));
Chris@16:                 }
Chris@16:               }
Chris@16:               t_day = day_type(day);
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'e': 
Chris@16:             {
Chris@16:               match_results mr;
Chris@16:               day = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 2, ' ');
Chris@16:               if(day == -1) {
Chris@16:                 if(sv_parser.match(sitr, stream_end, mr)) {
Chris@16:                   return date_type(static_cast<special_values>(mr.current_match));
Chris@16:                 }
Chris@16:               }
Chris@16:               t_day = day_type(day);
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'j': 
Chris@16:             {
Chris@16:               match_results mr;
Chris@16:               day_of_year = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 3);
Chris@16:               if(day_of_year == -1) {
Chris@16:                 if(sv_parser.match(sitr, stream_end, mr)) {
Chris@16:                   return date_type(static_cast<special_values>(mr.current_match));
Chris@16:                 }
Chris@16:               }
Chris@16:               // these next two lines are so we get an exception with bad input
Chris@16:               day_of_year_type t_day_of_year(1);
Chris@16:               t_day_of_year = day_of_year_type(day_of_year);
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'm': 
Chris@16:             {
Chris@16:               match_results mr;
Chris@16:               month = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 2);
Chris@16:               if(month == -1) {
Chris@16:                 if(sv_parser.match(sitr, stream_end, mr)) {
Chris@16:                   return date_type(static_cast<special_values>(mr.current_match));
Chris@16:                 }
Chris@16:               }
Chris@16:               t_month = month_type(month);
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'Y': 
Chris@16:             {
Chris@16:               match_results mr;
Chris@16:               year = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 4);
Chris@16:               if(year == -1) {
Chris@16:                 if(sv_parser.match(sitr, stream_end, mr)) {
Chris@16:                   return date_type(static_cast<special_values>(mr.current_match));
Chris@16:                 }
Chris@16:               }
Chris@16:               t_year = year_type(year);
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'y': 
Chris@16:             {
Chris@16:               match_results mr;
Chris@16:               year = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 2);
Chris@16:               if(year == -1) {
Chris@16:                 if(sv_parser.match(sitr, stream_end, mr)) {
Chris@16:                   return date_type(static_cast<special_values>(mr.current_match));
Chris@16:                 }
Chris@16:               }
Chris@16:               year += 2000; //make 2 digit years in this century
Chris@16:               t_year = year_type(year);
Chris@16:               break;
Chris@16:             }
Chris@16:           default:
Chris@16:             {} //ignore those we don't understand
Chris@16:             
Chris@16:           }//switch
Chris@16:           
Chris@16:         }
Chris@16:         else { // itr == '%', second consecutive
Chris@16:           sitr++;
Chris@16:         }
Chris@16:         
Chris@16:         itr++; //advance past format specifier
Chris@16:       }
Chris@16:       else {  //skip past chars in format and in buffer
Chris@16:         itr++;
Chris@16:         if (use_current_char) {
Chris@16:           use_current_char = false;
Chris@16:         }
Chris@16:         else {
Chris@16:           sitr++;
Chris@16:         }
Chris@16:       }
Chris@16:     }
Chris@16:     
Chris@16:     if (day_of_year > 0) {
Chris@16:       date_type d(static_cast<unsigned short>(year-1),12,31); //end of prior year
Chris@16:       return d + duration_type(day_of_year);
Chris@16:     }
Chris@16:     
Chris@16:     return date_type(t_year, t_month, t_day); // exceptions were thrown earlier 
Chris@16:                                         // if input was no good 
Chris@16:   }
Chris@16:  
Chris@16:   //! Throws bad_month if unable to parse
Chris@16:   month_type
Chris@16:   parse_month(std::istreambuf_iterator<charT>& sitr, 
Chris@16:              std::istreambuf_iterator<charT>& stream_end,
Chris@16:              string_type format_str) const
Chris@16:   {
Chris@16:     match_results mr;
Chris@16:     return parse_month(sitr, stream_end, format_str, mr);
Chris@16:   }
Chris@16:  
Chris@16:   //! Throws bad_month if unable to parse
Chris@16:   month_type
Chris@16:   parse_month(std::istreambuf_iterator<charT>& sitr, 
Chris@16:              std::istreambuf_iterator<charT>& stream_end,
Chris@16:              string_type format_str,
Chris@16:              match_results& mr) const
Chris@16:   {
Chris@16:     bool use_current_char = false;
Chris@16:     
Chris@16:     // skip leading whitespace
Chris@16:     while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; } 
Chris@16: 
Chris@16:     short month(0);
Chris@16:     
Chris@16:     const_itr itr(format_str.begin());
Chris@16:     while (itr != format_str.end() && (sitr != stream_end)) {
Chris@16:       if (*itr == '%') {
Chris@16:         if ( ++itr == format_str.end())
Chris@16:         	break;
Chris@16:         if (*itr != '%') {
Chris@16:           switch(*itr) {
Chris@16:           case 'b': 
Chris@16:             {
Chris@16:               mr = m_month_short_names.match(sitr, stream_end);
Chris@16:               month = mr.current_match;
Chris@16:               if (mr.has_remaining()) {
Chris@16:                 use_current_char = true;
Chris@16:               }
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'B': 
Chris@16:             {
Chris@16:               mr = m_month_long_names.match(sitr, stream_end);
Chris@16:               month = mr.current_match;
Chris@16:               if (mr.has_remaining()) {
Chris@16:                 use_current_char = true;
Chris@16:               }
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'm': 
Chris@16:             {
Chris@16:               month = var_string_to_int<short, charT>(sitr, stream_end, 2);
Chris@16:               // var_string_to_int returns -1 if parse failed. That will 
Chris@16:               // cause a bad_month exception to be thrown so we do nothing here
Chris@16:               break;
Chris@16:             }
Chris@16:           default:
Chris@16:             {} //ignore those we don't understand
Chris@16:             
Chris@16:           }//switch
Chris@16:           
Chris@16:         }
Chris@16:         else { // itr == '%', second consecutive
Chris@16:           sitr++;
Chris@16:         }
Chris@16:         
Chris@16:         itr++; //advance past format specifier
Chris@16:       }
Chris@16:       else {  //skip past chars in format and in buffer
Chris@16:         itr++;
Chris@16:         if (use_current_char) {
Chris@16:           use_current_char = false;
Chris@16:         }
Chris@16:         else {
Chris@16:           sitr++;
Chris@16:         }
Chris@16:       }
Chris@16:     }
Chris@16:     
Chris@16:     return month_type(month); // throws bad_month exception when values are zero
Chris@16:   }
Chris@16: 
Chris@16:   //! Expects 1 or 2 digits 1-31. Throws bad_day_of_month if unable to parse
Chris@16:   day_type
Chris@16:   parse_var_day_of_month(std::istreambuf_iterator<charT>& sitr, 
Chris@16:                          std::istreambuf_iterator<charT>& stream_end) const
Chris@16:   {
Chris@16:     // skip leading whitespace
Chris@16:     while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; } 
Chris@16: 
Chris@16:     return day_type(var_string_to_int<short, charT>(sitr, stream_end, 2));
Chris@16:   }
Chris@16:   //! Expects 2 digits 01-31. Throws bad_day_of_month if unable to parse
Chris@16:   day_type
Chris@16:   parse_day_of_month(std::istreambuf_iterator<charT>& sitr, 
Chris@16:                      std::istreambuf_iterator<charT>& stream_end) const
Chris@16:   {
Chris@16:     // skip leading whitespace
Chris@16:     while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; } 
Chris@16: 
Chris@16:     //return day_type(var_string_to_int<short, charT>(sitr, stream_end, 2));
Chris@16:     match_results mr;
Chris@16:     return day_type(fixed_string_to_int<short, charT>(sitr, stream_end, mr, 2));
Chris@16:   }
Chris@16: 
Chris@16:   day_of_week_type
Chris@16:   parse_weekday(std::istreambuf_iterator<charT>& sitr, 
Chris@16:              std::istreambuf_iterator<charT>& stream_end,
Chris@16:              string_type format_str) const
Chris@16:   {
Chris@16:     match_results mr;
Chris@16:     return parse_weekday(sitr, stream_end, format_str, mr);
Chris@16:   }
Chris@16:   day_of_week_type
Chris@16:   parse_weekday(std::istreambuf_iterator<charT>& sitr, 
Chris@16:              std::istreambuf_iterator<charT>& stream_end,
Chris@16:              string_type format_str,
Chris@16:              match_results& mr) const
Chris@16:   {
Chris@16:     bool use_current_char = false;
Chris@16:     
Chris@16:     // skip leading whitespace
Chris@16:     while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; } 
Chris@16: 
Chris@16:     short wkday(0);
Chris@16:     
Chris@16:     const_itr itr(format_str.begin());
Chris@16:     while (itr != format_str.end() && (sitr != stream_end)) {
Chris@16:       if (*itr == '%') {
Chris@16:         if ( ++itr == format_str.end())
Chris@16:         	break;
Chris@16:         if (*itr != '%') {
Chris@16:           switch(*itr) {
Chris@16:           case 'a': 
Chris@16:             {
Chris@16:               //this value is just throw away.  It could be used for
Chris@16:               //error checking potentially, but it isn't helpful in 
Chris@16:               //actually constructing the date - we just need to get it
Chris@16:               //out of the stream
Chris@16:               mr = m_weekday_short_names.match(sitr, stream_end);
Chris@16:               wkday = mr.current_match;
Chris@16:               if (mr.has_remaining()) {
Chris@16:                 use_current_char = true;
Chris@16:               }
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'A': 
Chris@16:             {
Chris@16:               //this value is just throw away.  It could be used for
Chris@16:               //error checking potentially, but it isn't helpful in 
Chris@16:               //actually constructing the date - we just need to get it
Chris@16:               //out of the stream
Chris@16:               mr = m_weekday_long_names.match(sitr, stream_end);
Chris@16:               wkday = mr.current_match;
Chris@16:               if (mr.has_remaining()) {
Chris@16:                 use_current_char = true;
Chris@16:               }
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'w':
Chris@16:             {
Chris@16:               // weekday as number 0-6, Sunday == 0
Chris@16:               wkday = var_string_to_int<short, charT>(sitr, stream_end, 2);
Chris@16:               break;
Chris@16:             }
Chris@16:           default:
Chris@16:             {} //ignore those we don't understand
Chris@16:             
Chris@16:           }//switch
Chris@16:           
Chris@16:         }
Chris@16:         else { // itr == '%', second consecutive
Chris@16:           sitr++;
Chris@16:         }
Chris@16:         
Chris@16:         itr++; //advance past format specifier
Chris@16:       }
Chris@16:       else {  //skip past chars in format and in buffer
Chris@16:         itr++;
Chris@16:         if (use_current_char) {
Chris@16:           use_current_char = false;
Chris@16:         }
Chris@16:         else {
Chris@16:           sitr++;
Chris@16:         }
Chris@16:       }
Chris@16:     }
Chris@16:     
Chris@16:     return day_of_week_type(wkday); // throws bad_day_of_month exception 
Chris@16:                                     // when values are zero
Chris@16:   }
Chris@16:   
Chris@16:   //! throws bad_year if unable to parse
Chris@16:   year_type
Chris@16:   parse_year(std::istreambuf_iterator<charT>& sitr, 
Chris@16:              std::istreambuf_iterator<charT>& stream_end,
Chris@16:              string_type format_str) const
Chris@16:   {
Chris@16:     match_results mr;
Chris@16:     return parse_year(sitr, stream_end, format_str, mr);
Chris@16:   }
Chris@16: 
Chris@16:   //! throws bad_year if unable to parse
Chris@16:   year_type
Chris@16:   parse_year(std::istreambuf_iterator<charT>& sitr, 
Chris@16:              std::istreambuf_iterator<charT>& stream_end,
Chris@16:              string_type format_str,
Chris@16:              match_results& mr) const
Chris@16:   {
Chris@16:     bool use_current_char = false;
Chris@16:     
Chris@16:     // skip leading whitespace
Chris@16:     while(std::isspace(*sitr) && sitr != stream_end) { ++sitr; } 
Chris@16: 
Chris@16:     unsigned short year(0);
Chris@16:     
Chris@16:     const_itr itr(format_str.begin());
Chris@16:     while (itr != format_str.end() && (sitr != stream_end)) {
Chris@16:       if (*itr == '%') {
Chris@16:         if ( ++itr == format_str.end())
Chris@16:         	break;
Chris@16:         if (*itr != '%') {
Chris@16:           //match_results mr;
Chris@16:           switch(*itr) {
Chris@16:           case 'Y':
Chris@16:             {
Chris@16:               // year from 4 digit string
Chris@16:               year = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 4);
Chris@16:               break;
Chris@16:             }
Chris@16:           case 'y':
Chris@16:             {
Chris@16:               // year from 2 digit string (no century)
Chris@16:               year = fixed_string_to_int<short, charT>(sitr, stream_end, mr, 2);
Chris@16:               year += 2000; //make 2 digit years in this century
Chris@16:               break;
Chris@16:             }
Chris@16:           default:
Chris@16:             {} //ignore those we don't understand
Chris@16:             
Chris@16:           }//switch
Chris@16:           
Chris@16:         }
Chris@16:         else { // itr == '%', second consecutive
Chris@16:           sitr++;
Chris@16:         }
Chris@16:         
Chris@16:         itr++; //advance past format specifier
Chris@16:       }
Chris@16:       else {  //skip past chars in format and in buffer
Chris@16:         itr++;
Chris@16:         if (use_current_char) {
Chris@16:           use_current_char = false;
Chris@16:         }
Chris@16:         else {
Chris@16:           sitr++;
Chris@16:         }
Chris@16:       }
Chris@16:     }
Chris@16:     
Chris@16:     return year_type(year); // throws bad_year exception when values are zero
Chris@16:   }
Chris@16:   
Chris@16:   
Chris@16:  private:
Chris@16:   string_type m_format;
Chris@16:   parse_tree_type m_month_short_names;
Chris@16:   parse_tree_type m_month_long_names;
Chris@16:   parse_tree_type m_weekday_short_names;
Chris@16:   parse_tree_type m_weekday_long_names;
Chris@16: 
Chris@16: };
Chris@16: 
Chris@16: } } //namespace
Chris@16: 
Chris@16: #endif
Chris@16: 
Chris@16: 
Chris@16: